Route guidance using text

ABSTRACT

A computer implemented method for performing route guidance using text includes obtaining an optimal route that connects a start point and an end point of a route input by a user; comparing a route history stored in a memory with the optimal route and extracting a route portion from the optimal route, the route portion being replaceable by a route portion in the route history; creating route guidance for the route portion extracted from the optimal route by using a text indication known to the user, the known text indication specifying the replaceable route portion in the route history; and creating route guidance for a route portion in the optimal route, the route portion being not replaceable by a route portion in the route history, by using a new text indication that specifies the route portion that is not replaceable.

DOMESTIC AND FOREIGN PRIORITY

This application is a continuation of U.S. patent application Ser. No.14/708,909, filed May 11, 2015, which claims priority to Japanese PatentApplication No. 2014-107621, filed May 24, 2014, and all the benefitsaccruing therefrom under 35 U.S.C. §119, the contents of which in itsentirety are herein incorporated by reference.

BACKGROUND

The present invention relates to route guidance, and more specifically,relates to a method performed by a computer for route guidance usingtext.

In emerging countries, for example, countries in Africa, terminalscalled feature phones or basic phones, which provide mainly telephonecall functions, are still the dominant type of mobile phone, andcommunication of information is actively performed using short messageservices (SMS). In such environments, text-based route guidance usingSMS to communicate a small amount of information needs to be assumedeven in the case of providing route guidance for vehicles and the like.Such route guidance has been provided on a trial basis in somecountries.

However, an amount of information that can be transmitted with one SMSmessage is limited to about 120 characters, and about 10 SMS messagesare needed to transmit information about an entire route. Therefore, inthe results of trials performed so far, participants have currentlygiven feedbacks and made complaints, such as “routes shown are toolong”.

As a solution to the above issue, an idea may be considered of furthersummarizing the content and transmitting route guidance. However, routeguidance itself is conveyed by text that is already simplified, andtherefore, an existing technique for text summarization cannot besuccessfully (effectively) applied. In the case of SMS, a user (on thereceiving side) cannot refer to a history, and therefore, a generalcache technique for saving graphs (data structures) is not applicable.

SUMMARY

In one embodiment, a computer implemented method for performing routeguidance using text includes obtaining an optimal route that connects astart point and an end point of a route input by a user; comparing aroute history stored in a memory with the optimal route and extracting aroute portion from the optimal route, the route portion beingreplaceable by a route portion in the route history; creating routeguidance for the route portion extracted from the optimal route by usinga text indication known to the user, the known text indicationspecifying the replaceable route portion in the route history; andcreating route guidance for a route portion in the optimal route, theroute portion being not replaceable by a route portion in the routehistory, by using a new text indication that specifies the route portionthat is not replaceable.

In another embodiment, a system for performing route guidance using textincludes a processing device configured t obtain an optimal route thatconnects a start point and an end point of a route input by a user;compare a route history stored in a memory with the optimal route andextract a route portion from the optimal route, the route portion beingreplaceable by a route portion in the route history; create routeguidance for the route portion extracted from the optimal route by usinga text indication known to the user, the known text indicationspecifying the replaceable route portion in the route history; andcreate route guidance for a route portion in the optimal route, theroute portion being not replaceable by a route portion in the routehistory, by using a new text indication that specifies the route portionthat is not replaceable.

In another embodiment, a computer readable storage medium havingcomputer readable instructions stored thereon that, when executed by acomputer, implements a method for performing route guidance using text.The method includes obtaining an optimal route that connects a startpoint and an end point of a route input by a user; comparing a routehistory stored in a memory with the optimal route and extracting a routeportion from the optimal route, the route portion being replaceable by aroute portion in the route history; creating route guidance for theroute portion extracted from the optimal route by using a textindication known to the user, the known text indication specifying thereplaceable route portion in the route history; and creating routeguidance for a route portion in the optimal route, the route portionbeing not replaceable by a route portion in the route history, by usinga new text indication that specifies the route portion that is notreplaceable.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram illustrating an example of a basicconfiguration of a network system suitable for implementing embodimentsof the invention.

FIG. 2 is a diagram illustrating a configuration of a computer thatperforms embodiment of the present invention.

FIG. 3 is a flowchart that illustrates a method for performing routeguidance using text, in accordance with an embodiment of the presentinvention.

FIG. 4 is a diagram illustrating routes in an exemplary embodiment towhich the present invention is applied.

FIGS. 5( a) and 5(b) are diagrams illustrating route guidance in anexemplary embodiment of the present invention.

DETAILED DESCRIPTION

Embodiments of the present invention provide a method capable ofreducing the amount of information to be transmitted without decreasingthe amount of information that is desired to be communicated to userswhen route guidance using text is to be transmitted.

In particular, embodiments of the present invention provide a computerimplement method for performing route guidance using text. The methodincludes obtaining an optimal route that connects a start point and anend point of a route input by a user, comparing a route history storedin a memory with the optimal route and extracting a route portion fromthe optimal route, the route portion being replaceable by a routeportion in the route history, creating route guidance for the routeportion extracted from the optimal route by using a text indicationknown to the user, the known text indication specifying the replaceableroute portion in the route history, and creating route guidance for aroute portion in the optimal route, the route portion being notreplaceable by a route portion in the route history, by using a new textindication that specifies the route portion that is not replaceable.

According to one aspect of the present invention, the optimal route andthe route history are each obtained as a graph that includes a pluralityof nodes and edges between two adjacent nodes. A route portion in theroute history and a route portion in the optimal route each include thenodes and the edges that form part of the graph.

According to one aspect of the present invention, the known textindication and the new text indication are created for each of at leastone edge that forms part of the graph, or are created as one textindication that corresponds to a plurality of successive edges that formpart of the graph.

According to one aspect of the present invention, extracting areplaceable route portion from the optimal route includes a step ofextracting corresponding route portions from among a plurality of routeportions in the route history in descending order of the number of pastextractions.

According to one aspect of the present invention, extracting areplaceable route portion from the optimal route includes extracting aroute portion from the optimal route, the route portion overlapping aroute portion in the route history.

According to one aspect of the present invention, creating routeguidance using a text indication known to the user, the known textindication specifying the replaceable route portion in the routehistory, includes creating route guidance so as to enable the user touniquely recognize the route portion specified by the known textindication.

According to one aspect of the present invention, the method furtherincludes transmitting the route guidance created by using the known textindication and the new text indication to a terminal operable by theuser, and displaying, on a display screen of the terminal, the routeguidance that has been received.

An embodiment of the present invention will be described with referenceto the drawings. FIG. 1 is a block diagram illustrating an example of abasic configuration of a network system to which a method of the presentinvention is applied. A network system 100 includes a server 10 andterminals 20 connected to the server 10 via networks (communicationpaths) 30 so as to enable communication. Examples of the terminal 20include mobile phones called feature phones or basic phones, andsmartphones. The terminal 20 may be a terminal installed in a form oftransportation, such as a vehicle. The terminal 20 includes a displayscreen (display) 201 for displaying route guidance of the presentinvention. Note that, in FIG. 1, only three terminals 20 areillustrated, however, needless to say, a plurality of terminals of anynumber which can perform communication may be included.

FIG. 2 is a diagram illustrating an example of a configuration of theserver 10 in FIG. 1. The server 10 includes a central processing unit(CPU) 101, a storage means 102, and various I/Fs 104, which areconnected to one another via a bus 103. The term “various I/Fs 104” isused as a generic term that includes an input I/F, an output I/F, anexternal storage I/F, an external communication I/F, and the like, andthese I/Fs are respectively connected to an input means 105, such as akeyboard or a mouse, a display means 106, such as a CRT or an LCD, anexternal storage means 107, such as a USB-connected semiconductor memoryor an HDD, and the like. The storage means 102 may include asemiconductor memory, such as a RAM or a ROM, an HDD, and the like. Themethod of the present invention is implemented by the server 10 loadingand executing predetermined software stored in the storage means 102 or107, for example.

The flow of the method of the present invention will be described withreference to the drawings. FIG. 3 is a flowchart illustrating a basicflow of the method of the present invention. In operation S11 in FIG. 3,an optimal route that connects a start point and an end point of a routeinput by a user is obtained. Information about the start point and theend point of the route is transmitted by the user from the terminal 20to the server 10. The server 10 calculates an optimal route using anyexisting route finding algorithm on the basis of the receivedinformation.

A route described in the present invention including an optimal route isobtained as a graph (data structure) that includes a plurality of nodesand edges between two adjacent nodes. FIG. 4 illustrates an image ofroutes in an exemplary embodiment to which the present invention isapplied. In FIG. 4, two routes which a vehicle 40 travels, that is, aroute A represented by a continuous line and a route B represented by adashed line, both of which extend from a start point S to an end pointG, are illustrated. Note that in sections where both routes overlap (asection between S and P and a section between Q and G), the dashed lineis hidden behind the continuous line and only the continuous line isvisible. Referring to FIG. 4 to obtain an image, a plurality of nodescorrespond to points (positions) represented by white circles 50, andedges between nodes correspond to lines 55. A node can be selected asthe position of an intersection of roads, for example.

Next, in operation S12, the optimal route obtained in operation S11 iscompared with a route history stored in a memory, and a route portion inthe optimal route which is replaceable by a route portion in the routehistory is extracted. The route history stored in the memory includesroutes which have been registered as favorites and which a user used atleast several times in the past, for example. A route portion includesnodes (for example, the white circles 50 in FIG. 4), and edges (forexample, the lines 55 in FIG. 4) which form part of the graph describedabove.

A replaceable route potion in an optimal route can be extracted asfollows.

(a) Routes which a user has registered as favorites among routescommunicated in the past remain stored and are compared with a routethat is to be communicated to thereby extract a set α that includesknown subgraphs covered by stored routes and a set β that includesunknown subgraphs. Note that, stored routes are given priority levels,and a subgraph belonging to the set α has accompanying information thatindicates a stored route of the highest priority among stored routes bywhich the subgraph is covered.

(b) From successive subgraphs that belong to the set α extracted in theabove process (a), all edges having the same accompanying informationare rounded as one edge. To the rounded edge, accompanying informationindicating a stored route of the highest priority is passed. Note thatthe processes (a) and (b) are performed on the basis of the routehistory of the server 10 (transmitting side), not on the basis of aroute history of the terminal 20 (receiving side), which is a feature ofthe present invention.

Extraction of a route portion in operation S12 may include extraction ofa route portion from the optimal route, this route portion overlapping aroute portion in the route history. Here, overlapping means that routesoverlap (are identical). In the example of routes in FIG. 4, the sectionbetween S and P and the section between Q and G in the route A and theroute B include overlapping route portions, which corresponds to theabove. Furthermore, in the case where a plurality of route portions inan optimal route are replaceable, it is possible to extractcorresponding route portions from a plurality of route portions in theroute history in descending order of the number of past extractions, forexample.

Next, in operation S13, for the route portion extracted from the optimalroute, route guidance is created using a text indication known to theuser which specifies the replaceable route portion in the route history.Here, a text indication known to a user means a text indication suchthat the user can uniquely recognize a corresponding route when the usersees the text indication. For example, a route number, such as route 1,a well-known name including a street name, such as AAA street, a routewhich a user repeatedly travels, clearly remembers, and has registeredas a favorite with a unique name, and a specific section of the routeare text indications.

A known text indication is created for each of at least one edge thatforms part of the graph described above, or is created as one textindication that corresponds to a plurality of (two or more) successiveedges that form part of the graph. In the example of routes in FIG. 4, aknown text indication is created for one edge 55 between two adjacentnodes, or two or more successive edges 55, for example.

In the creation described above, in the case where the rounded edgeobtained in the above process (b) in operation S13 described above isused, a text for route guidance for the edge is created on the basis ofthe accompanying information about a stored route. For example, a textis created as follows.

“Go to intersection Y according to the registered route X” or

“Go to destination W according to the registered route Z”

Next, in operation S14, a new text indication that specifies a routeportion in the optimal route which is not replaceable by a route portionin the route history is used, and route guidance about the route portionthat is not replaceable is created. A text indication is created foreach of at least one edge that forms part of the graph described above,or is created as one text indication that corresponds to a plurality of(two or more) successive edges that form part of the graph similarly tooperation S13. In the creation described here, for edges that belong tothe set β that includes unknown subgraphs extracted in the above process(a) in operation S13 described above, a guidance text is created using atechnique according to the related art employed in existing systems.

Next, in operation S15, the texts for route guidance created inoperations S13 and S14 are concatenated and transmitted to the terminal20 of the user as a single, optimal route guidance message. Thistransmission is performed via the network (communication path) 30 usingSMS, for example. Next, in operation S16, the received optimal routeguidance is displayed on the display screen 201 of the terminal 20. Theoptimal route guidance may be simultaneously communicated to the userfrom the terminal 20 by audio.

Exemplary Embodiment

An exemplary embodiment of the present invention will be described withreference to FIG. 5. FIG. 5 is a diagram illustrating route guidance inan exemplary embodiment of the present invention. FIG. 5( a) illustratestexts for route guidance before application of the present invention,and FIG. 5( b) illustrates texts for route guidance after application ofthe present invention. When the texts before and after application arecompared, it is found that the individual pieces of guidance (texts)labelled 2 and 3 in FIG. 5( a) are simplified into the guidance 2′ inFIG. 5( b), and the individual pieces of guidance labelled 6 to 9 inFIG. 5( a) are simplified into the guidance 5′ in FIG. 5( b). Suchsimplification can reduce the amount of data to be transmitted by thenumber of decreased characters. At the same time, a user can grasp theguided route (optimal route) more exactly and briefly. Thesimplification illustrated in FIG. 5( b) is specifically implemented byan algorithm described below, for example.

<Assumption>

(a) A set of routes registered by a user A is denoted by SR={R₁, R₂, . .. , R_(a)}. It is assumed that R_(a) indicates each route that the userA has registered as a favorite among routes shown by the system (server)to the user A. It is also assumed that the routes are sorted inaccordance with the priority levels determined by the user A.

(b) Each route is represented as a set of pieces of basic informationR_(a)M_(b) for an SMS message, that is, R_(a)={R_(a)M₁, R_(a)M₂, . . . ,R_(a)M_(b)}, the pieces of basic information being listed in the orderof guidance. R_(a)M_(b) includes SI (an intersection that is the startpoint of the guidance), EI (an intersection that is the end point of theguidance), D (the distance between the start point and the end point),EI_(d) (description of EI), EI_(a) (an action to be taken at EI), andEI_(r) (the name of a route to be taken at EI).

(c) A new route NR is also represented as a set of pieces of basicinformation NRM_(c) for an SMS message, that is, NR={NRM₁, NRM₂, . . . ,NRM_(c)}.

<Algorithm>

(1) i is set to 1, and m is set to NRM_(i) (that is, i=1 and m=NRM_(i)).

(2) R_(a) that is given the highest priority and that includes part ofor matches the longest series of successive L items, that is, [NRM_(i),. . . , NRM_(i+L−1)], is selected as R_(x), the L items being successiveand starting with m, L exceeding a predetermined threshold X. Thematched portion of R_(x) is represented by [R_(x)M_(y), . . . ,R_(x)M_(y+L−1)]. If a corresponding R_(a) does not exist, in the case ofi=k−1, the processing ends. Otherwise, i is incremented by 1 and m isset to NRM_(i) (that is, i=i+1 and m=NRM_(i)), and the process (2) isrepeated.

(3) In the case of i=1 and L=k, this means NRεR_(a). Therefore,replacement by the following message is performed, and the processingproceeds to the process (6) below.

“Go to destination according to the route R_(a)”

(4) NRM_(i) is compared with R_(x)M_(y). If NRM_(i) includes a routethat is not covered by R_(x)M_(y), a route from NRM_(i)(SI) toR_(x)M_(y)(SI) is created. However, if NRM_(i) is entirely covered byR_(x)M_(y), a route is not created here. Then, a route that is to travelis generated in accordance with R_(x). Furthermore, NRM_(i+L−1) iscompared with R_(x)M_(y+L−1). If NRM_(i+L−1) includes a route that isnot covered by R_(x)M_(y+L−1), a route from R_(x)M_(y+L−1)(EI) toNRM_(i)(EI) is also generated. However, if NRM_(i+L−1) is entirelycovered by R_(x)M_(y+L−1), a route is not created here. In this case, aroute that is finally generated is as follows.

“at RxMy(SI) after D′ (=distance from NRM_(i)(SI) to R_(x)M_(y)(SI),follow the route R_(x)”, or simply

“follow the route Rx”

(“at R_(x)M_(y+L−1)(EI), NRM_(i)(EI_(a)) onto NRM_(i)(EI_(r))”)

(5) However, if i=k−L−1 is satisfied and NRM′_(i+L−1) is covered byR_(x)M_(y+L−1) in the process (4), arrival to the destination can beattained with the route. Therefore, the last route is created byreplacement by the following message.

“Go to destination according to the route R_(x)”

(6) i is incremented by L (that is, i=i+L).

In the case of i>k−x, the processing ends. Otherwise, m is set toNRM_(i) (that is, m=NRM_(i)), and the processing returns to the process(2) above.

While an embodiment of the present invention has been described withreference to the drawings, the present invention is not limited to theembodiment. The present invention may be implemented while makingvarious improvements, modifications, or alterations on the embodiment onthe basis of the knowledge of those skilled in the art without departingfrom the spirit of the present invention.

REFERENCE SIGNS LIST

-   -   10: server    -   20: terminal    -   30: network (communication path)    -   40: vehicle    -   50: node    -   55: edge    -   100: network system    -   201: display screen

1. A computer implemented method for performing route guidance usingtext, the method comprising: obtaining an optimal route that connects astart point and an end point of a route input by a user; comparing aroute history stored in a memory with the optimal route and extracting aroute portion from the optimal route, the route portion beingreplaceable by a route portion in the route history; creating routeguidance for the route portion extracted from the optimal route by usinga text indication known to the user, the known text indicationspecifying the replaceable route portion in the route history; andcreating route guidance for a route portion in the optimal route, theroute portion being not replaceable by a route portion in the routehistory, by using a new text indication that specifies the route portionthat is not replaceable.
 2. The method of claim 1, wherein the optimalroute and the route history are each obtained as a graph that includes aplurality of nodes and edges between two adjacent nodes, and a routeportion in the route history and a route portion in the optimal routeeach include the nodes and the edges that form part of the graph.
 3. Themethod of claim 2, wherein the known text indication and the new textindication are created for each of at least one edge that forms part ofthe graph.
 4. The method of claim 2, wherein the known text indicationand the new text indication are created as one text indication thatcorresponds to a plurality of successive edges that form part of thegraph.
 5. The method of claim 1, wherein extracting a replaceable routeportion from the optimal route includes extracting corresponding routeportions from among a plurality of route portions in the route historyin descending order of the number of past extractions.
 6. The method ofclaim 1, wherein extracting a replaceable route portion from the optimalroute includes extracting a route portion from the optimal route, theroute portion overlapping a route portion in the route history.
 7. Themethod of claim 1, wherein creating route guidance using a textindication known to the user, the known text indication specifying thereplaceable route portion in the route history, includes creating routeguidance so as to enable the user to uniquely recognize the routeportion specified by the known text indication.
 8. The method of claim1, further comprising: transmitting the route guidance created by usingthe known text indication and the new text indication to a terminaloperable by the user; and displaying, on a display screen of theterminal, the route guidance that has been received.
 9. The method ofclaim 8, wherein the route guidance is route guidance for carnavigation, and the start point and the end point of the route are aplace of departure and a destination of a travel route respectively.